(a) Field of the Invention
The invention relates to a trocar sleeve having a valve piston (trumpet valve) which can be brought into the open position against spring action by means of pressure on the actuation handle, which valve piston has a bore corresponding to the diameter of the access channel of the trocar sleeve.
(b) Description of the Prior Art
In such generally known trocar sleeves fitted with a trumpet valve (hand-actuated piston valve), the trumpet valve standing under permanent spring tension closes the channel of the trocar sleeve in a gas-tight manner when the trocar is removed and when instruments are exchanged.
However, known trocar sleeves of this type have the disadvantage that the trumpet valve standing under permanent spring tension in its channel presses on the instrument introduced, and hence inhibits its rotatability and its ability for longitudinal displacement. The sensitive handling of the instrument during endoscopy is thus impaired. In addition, damage to the instrument surface may thus occur, in particular for instruments with isolated surfaces.
The object of the invention is therefore to design a trocar sleeve with trumpet valve, so that the spring-loaded valve piston does not inhibit the mobility of an instrument when it is guided through the trocar sleeve and does not damage its surface, and in that the access channel of the trocar sleeve can be closed quickly in a gas-tight manner by means of simple operation when instruments are changed.